The forage crops with which the present invention is concerned include hay which comprises one or more perennial grasses, e.g., alfalfa, trefoil, clovers, annuals such as Sudan grass, sorghum, Sudan hybrids, timothy and bluestem. The forage crops with which the present invention is concerned also include dehydrated alfalfa, i.e., alfalfa which has been artificially dried.
In processing hay or dried forage crops of the type mentioned above, the grasses are cut when mature and are allowed to partially dry on the ground. Frequent turning is required in order to speed drying. The moisture content of the grasses when cut will usually be in the range of 60-75% by weight. In order for the grasses to be successfully stored without fermentation beginning during storage or mold attacking the grasses, they must be dried to a moisture content below 10%. At this point the grasses are compressed into bales and they are stored in this form in covered areas on the farm or in barns.
Alfalfa, which is actually a legume, is harvested when mature. The cut alfalfa is then artificially dried, usually by using hot air resulting from the combustion of natural gas, fuel oil and indirectly by the use of high pressure steam flowing through heating coils. The alfalfa is usually cut into small pieces before being dried.
As pointed out above, the moisture content of hay at cutting time is very high, about 60-75% by weight. Reduction of this moisture to below 10% by weight, usually 7% by weight, can be effected by allowing the hay to dry in the field but this process is frequently interrupted by weather conditions. If rain falls on the grasses as they are drying on the ground, the grasses must be turned in order to prevent them from being attacked by molds or bacteria. Obviously, this increases the labor required to harvest a crop of hay.
If hay is baled before it has been sufficiently dried, the high moisture content will permit yeasts and molds to grow in the bale. This attack by microorganisms is accompanied by a very drastic increase in temperature. Consequently, when a large quantity of hay is stored in a barn, the temperature frequently reaches a high enough point for combustion to take place. The result is a sudden fire of the entire collection of hay, with resulting losses of the hay and the housing structure. This is a well known and frequently occurring difficulty on farms.